package niuke;

import java.util.Scanner;

//输入包括一行,四个整数x, f, d, p(1 <= x,f,d,p <= 2 * 10^9),以空格分割

public class 独立的牛牛 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int x = scanner.nextInt();
        int f = scanner.nextInt();
        int d = scanner.nextInt();
        int p = scanner.nextInt();
        int count = 0;
        while (x>0){
            if(f>0){
                d = d - x ;
                f--;
            }
            else {
                d = d - x - p;
            }
            if(d<0){
                break;
            }
            count++;
        }
        System.out.println(count);
    }
}
